San Joaquin Valley Air Pollution Control District officials warned residents that areas of blowing dust can result in unhealthy concentrations of particulate matter. Exposure to particulate pollution can cause serious health issues such as lung disease, asthma attacks, bronchitis and respiratory infections.

Winds are expected to calm to 5 to 10 mph by Thursday afternoon in Merced and Mariposa counties, Spector said.

Temperatures are also expected to drop. The high 90s experienced in recent days in Merced will give way to low 80s by the weekend, and Mariposa’s high 80s will become mid-70s, according to forecasters.